Reinforcement details for slabs-on-ground with crack control factors

While designing the slabs, which are built up on ground, the crack control factors should be taken into account. Given below, reinforcement details for slabs-on-ground.

The density and the design of the slabs-on-ground are dependent on the cracks which are developed because of the external loading. The calculation for slab thickness is made on the basis of the suppositions of a slab being unreinforced and un-cracked.

For specific situations of slabs on ground, the steel reinforcement can offer a great solution. The characteristics of this method contains the following :-

1. The limiting of cracks occur because of shrinkage
2. Apply bigger joint spacing that is larger than the unreinforced slabs
3. The possibilities for cracks development may be avoided by provision for moment capacity and constancy for those areas.
4. Cracking can’t be resisted with the integration of reinforcement. These elements allow in minimizing or adjusting the produced crack width by genuinely raising the frequency of cracks that is created.

If a reinforcement design is proportioned and arranged perfectly, it can allow to restrain the width of the crack significantly and therefore the serviceability period of the slab is not impacted.

Thickness Design Methods for Slabs-on-Ground Construction

When reinforcement in the slab design is applied increasingly, the un-cracked strength of the slab is slightly affected. The various methods for thickness design like Pickett’s Analysis Method (PCA), WRI (Wire Reinforcement Institute) Design Method and COE methods can be employed for creating the design of slabs on ground with reinforcement.

Reinforcement for Slabs-on ground for Crack Width Control Only

The width of crack can be restrained by reinforcement on the basis of the two factors like the joint spacing and the thickness of the slab. Otherwise we can define the crack width control as a function of joint space and slab thickness.

There should be a minimum steel ratio of 0.5% of the slab cross section to facilitate the saw cut of contraction joints to be removed.

When the reinforcement is arranged, it is suggested to set the reinforcement bars nearer to the surface of the slab top surface devoid of compromising the minimum concrete coverage over the reinforcement.

Reinforcement details for slabs-on-ground with crack control factors

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Published By
Arka Roy
http://www.constructioncost.co
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7 Basic Tests of Bricks to ensure it’s quality

This construction video tutorial briefly explains what the most important brick test procedures are generally undertaken in the construction jobsite.

The details of the tests are given below :-

Compressive Test – It is performed to verify the strength of a brick. Under this test 5 samples of bricks are chosen randomly and sent them to laboratory and apply pressure on various bricks through a crushing machine. Now, take the average of all the results produced. If the averages is similar to 3.5 N/mm2, the quality of the bricks are good.

Water absorption Test – Under this test the bricks are selected in completely dry condition and taken their weight as W1. Then submerge them in water for 24 hours. Again, taken their (wet bricks) weight after 24 hours and named them as W2. Now find out the average with the following formula :

Water Absorption % = W2 – W1/W1 x 100

The recommended absorption rate should be between 15% – 20% for a good quality brick.

Impact Test – This test ensures the proper bond in a brick so that it can’t break easily. Under this test few bricks are selected and dropped them from a height of 1 meter.

If the bricks are broken, then impact test will come as failed. Contrarily, if these bricks are not broken, the test result will be considered as passed and the bricks are considered as good quality bricks.

Dimension Tolerance Test – In this test shape, size and colors of the bricks are checked. Under this test, 20 bricks are selected and arranged in a straight line. Then we take a sample of standard brick and tally it’s size, shape and color with the bricks arranged in a straight line. If they match with the sample bricks, the bricks should be treated as good quality bricks.

Soundness Test – In this test two are chosen randomly and hit with each other, if metallic sound is produced and the bricks remain unbroken then these bricks are considered as good quality bricks.

Hardness Test – In this test, a metal or other object is used to put scratches on the bricks. If scratches are not produced, then these bricks are hard and treated as good quality bricks.

Structure Test – In this test, a brick is chosen and broken from the middle, if there are no cracks, holes, impurities found inside the bricks, then the structures are strong and these bricks are treated as good quality bricks.

To watch online demonstration, go through the following video tutorial.

7 Basic Tests of Bricks to ensure it’s quality

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Published By
Arka Roy
http://www.constructioncost.co
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Common types of pipe fittings in a plumbing system

In this construction video tutorial, you will gather knowledge on various types of pipe fittings which are generally utilized in plumbing system. The video is very useful for the mechanical engineers and other construction professionals.

The role of a fitting in pipe systems is to attach straight pipe or tubing sections, adjust with various sizes or shapes and for other purposes, like regulating (or measuring) fluid flow.


In a plumbing system, the following types of fittings are used :-

Elbow – An elbow is set up among two lengths of pipe (or tubing) to facilitate changing the direction of flow. Normally, there are different types of elbows like 90° or 45° or 22.5°angle. The ends are machined for butt welding, threaded (generally female), or socketed. When the sizes for ends vary, it is called a reducing (or reducer) elbow.

Reducer – A reducer is provided for accommodating a change in pipe size to match hydraulic flow requirements of the system or adjust with current piping of a diverse size. Generally reducers remain concentric, but eccentric reducers are also utilized if required to sustain the top- or bottom-of-pipe level.

Coupling – A coupling attaches two pipes. If their sizes fluctuate, the fitting is called as a reducing coupling, reducer, or an adapter. Two types of couplings are available like “regular” and “slip”.

A regular coupling contains a small ridge or stop inside, to avoid over-insertion of a pipe, and consequently under-insertion of the other pipe segment (which may occur in a defective connection). A slip coupling alias a repair coupling is purposely developed devoid of this internal stop, to facilitate it for being slipped into place in rigid locations.

Union – A union is required to disconnect the pipes securely for maintenance purpose as well as for substituting the fixtures. With union, connection and disconnection can be smoothly done several times as per requirement. It comprises of three parts like a nut, a female end and a male end. If the female and male ends are united, the joint is sealed with nuts by pressing the two ends firmly together.

Tee – A tee is applied to unite (or separate) fluid flow. There are female thread sockets, solvent-weld sockets or opposed solvent-weld sockets and a female-threaded side outlet for it. It is possible to attach pipes having various diameters or adjust the direction of a pipe run, or both.

Cross – Crosses contain one inlet and three outlets (or contrary), and frequently comprise of solvent-welded socket or female-threaded ends. Cross fittings may strain pipes when temperature fluctuates as they are situated at the center of four connection points.

Plug – A plug sets within the pipe segment or fitting to which it is associated. In a threaded plumbing system, plugs contain male threads. Different plug types are available which range from mechanical, pneumatic-disk, single-size pneumatic rubber, multi-size pneumatic and flow-through, and high-pressure.

Cap – Caps, normally liquid- or gas-tight, provide a cover to the open end of a pipe. A cap is connected with the outside of a pipe, and may contain a solvent-weld socket end or a female-threaded interior. The outside of an industrial cap may come in various shapes like round, square, rectangular, U- or I-shaped, or may have a handgrip.

To gather more information, watch the following exclusive video tutorial.

Common types of pipe fittings in a plumbing system

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Published By
Arka Roy
http://www.constructioncost.co
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Benefits of concrete covers blocks in RCC work

This construction video tutorial will guide you to make concrete cover block or rebar spacer at a reasonable cost.

A rebar spacer belongs to a object that fastens the reinforcing steel or “rebar” in reinforced concrete structures since the rebar is amassed in place before the pouring of final concrete. The spacers are remained in place for the pour to set the reinforcing in place, and turn into a permanent part of the structure.

When RCC work is going on, implanting steel in concrete (called as cover) is a vital process for resisting rebar from decaying as well as arranging fire protection to the rebar. If the proposed cover is not arranged, the rebar will start to decay in due course of time and will lead to collapsing of the structure beforehand. So, cover blocks can extend the life of the structure considerably without incurring so much expenses.

The exact amount of cover is set by the application and the environment (e.g., is the RCC under water, etc.)

In India, following are considered as the standard size for the covers :

Slab : 20 mm
Beam : 25 mm
Column : 40 mm
Foundation : 50 mm

 

Concrete covers ensure the accurate position of steel, thus allowing in the practical application of the theoretical specifications of concrete construction. The cover of the steel concerning a specific construction component (for instance in a concrete slab or a beam) should be usually constant inside the element.

The application of covers can be beneficial to the areas where high earthquake activity along with corrosive environment (like proximity to salt water of sea) occurs.

Benefits of concrete covers blocks in RCC work

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Published By
Arka Roy
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Step-by-step guidelines to develop a concrete block wall

A concrete block wall is formed with standard size concrete blocks. The standard size belongs to 8 inches. The sizes of the blocks may differentiate based on the design parameters and standards fixed by an engineer for the concrete structure.

A structure that is build up with concrete block is susceptible to concrete corrosion. Therefore, blocks are pre-coated to resist corrosion in the concrete block wall structure.

This construction video tutorial briefly shows how to construct a 20 feet long block wall from scratch with your own effort.

The block wall is built up on the basis of the following specification :-

Grade N units should be used for concrete blocks.

F’C (the specified compressive strength for concrete) should be 2500 psi for footing.

Reinforcing Steel should have been A615 Grade 40 or 60.

Fill all cells having steel with grout along with bond beam.

The wall should have been plumb and all block courses should be level.
Reinforcing steel splices should be at least 24”.

 

 The first course should be arranged in fresh concrete for footing.
No of wall or fence should be permissible inside 36” of a fire hydrant and no wall, fence or foundation should be permissible inside 12” of a water meter.

Makin proper plan to adjust the height, location and design of the wall on the basis of the zone, location on the community design standards. Planning should be sanctioned before any permit is issued.

Step-by-step guidelines to develop a concrete block wall

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Published By
Arka Roy
http://www.constructioncost.co
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Some useful tips to develop and pour concrete stairs

The renowned concrete contractor, David Odell, has presented an exclusive construction video tutorial that provides some useful construction tips on how to develop and pour concrete stairs (10 steps of stairs).

These are the basic steps for developing concrete stairways. This video will guide you to build up your own concrete stairs. Steps shown in this video comprise of laying out the size, arranging the sub-base, developing the forms, pouring, finishing and curing the concrete from starting to completion.

A “riser” refers to the vertical surface of the step and a “tread” refers to the horizontal surface of the step. To define the whole size of the concrete stairs, initially, you should work out the total rise and run of the steps you are going to form.

To learn the complete process, watch the following video tutorial.

Some useful tips to develop and pour concrete stairs

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Published By
Arka Roy
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Characteristics of Mass Concrete

Mass concrete is made with solid structures (> 80 cm). These structures frequently contain a greater volume. It signifies that large volumes of concrete should be set up in a short time. It needs highly well-organized planning and competent methods.

Mass concrete is applied for:

 Foundations for large loads
 Foundations for buoyancy control
 Solid walls (e.g. radiation protection)
 Infill concrete

The following major issues are formed with these enormous structures:

 Extreme internal and external temperature discrepancies throughout setting and hardening
 Excessive maximum temperatures
 High internal and external temperature deviations and as a result forced shrinkage
 Secondary consolidation (settling) of the concrete and as a result cracking occurs over the top reinforcement layers and also settlement under the reinforcement bars

Riska: All of these issues can lead to cracks and cement matrix defects assumed to be “skin or surface cracks” which may happen if the external/internal temperature variation is more than 15 °C or the outer layers can contract because of their initial drying out. Usually, the depth of skin cracks is few centimeters and can close again later.

Proper Measurement:

 Utilize cements with low heat development
 Low water content (curtailment in w/c ratio)
 Biggest possible maximum particle size (e.g. 0–50 rather than 0–32)
 If required, chill the aggregates to have a low initial fresh concrete temperature
 Set the concrete in layers (layer thickness < 80 cm)
 Restrain the bottom layers to make sure that the entire section is recompacted as soon as the top layer is set
 Start curing by applying thermal insulation methods
 Make sure the proper design and circulation of joints and concreting sections, so that heat can be dissipated and the temperature developments and deviations can be adjusted

Characteristics of Mass Concrete

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Published By
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Brief demonstration of drywall estimating template in excel

This construction video tutorial provides the demonstration of user-friendly and spreadsheet based drywall estimating software.

It becomes difficult for the contractors to estimate and finish takeoff from drywall works. But this video shows how to make the process simple. In a drywall estimating process, the following steps should be included :-

Workout the Square Footage

Estimate Drywall Boards

Estimate Drywall Tape

Estimate Joint Compound

Estimate Drywall Screws

Estimate Corner Beads

Estimate Drywall Miscellaneous

Estimate Other Components

To learn the complete process, watch the following video tutorial.

Brief demonstration of drywall estimating template in excel

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Published By
Arka Roy
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How to make design of concrete corbel with spreadsheet

If you want to be familiar with the detailed process necessary for creating the design of a RCC Corbel in excel based spreadsheet following ACI 95, then you should go through the following construction video tutorial.

In architectural term a corbel stands for a structural piece (a type of bracket) made of stone, wood or metal that is overhanged from a wall to bear an oppressive weight. In brief, a corbel refers to a solid piece of material in the wall.

Corbels are mostly utilized in precast concrete construction to provide support to main beams and girders.

ACI 318-95/318R-95 is defined as building code requirements for Structural Concrete & Commentary.

ACI 318-95 offers good information to the engineers and designer. The most significant modification included in the new code is that references to “reinforced concrete” are turned into “structural concrete.”

To learn the complete process, watch the following video tutorial.

How to make design of concrete corbel with spreadsheet

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Published By
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How to design a beam in excel with coefficient method

This construction video tutorial sifts through the process for evaluating engineering drawing easily.

This construction video tutorial provides detailed guidelines on how to use excel based spreadsheet to design a beam. Here coefficient method is applied for designing purpose.

The calculation is made on the basis of the following drawings :-

  1. Typical floor plan
    b. Ground floor plan
    c. Column Layout
    d. Beam Column Layout

The coefficient method refers to a rapid hand-system that can be used for computing the moments in two-way slabs supported with edge beams. This method was initially contained in the 1963 edition of the ACI code as a method for creating design of two-way slabs which are supported on all four sides through walls, steel beams, or deep beams. The most recent version of the ACI code 318 does not contain the coefficient method but you can apply it for two slab systems with edge beams.

This method employs tables of moment coefficients for different types of slab edge conditions. The coefficients are dependent on elastic analysis but also comprises of considerations for inelastic moment redistribution.

To learn the complete process, watch the following video tutorial

How to design a beam in excel with coefficient method

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Published By
Arka Roy
http://www.constructioncost.co
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